1. Field of the Invention
This invention relates to a steering wheel switching circuit for a plurality of switches installed on a steering wheel for the purpose of controlling component parts, such as electrical equipment and the like, of automobile and the like installed on a car body side.
2. Description of the Prior Art
Recent advancements automotive electronics have made it possible and necessary to perform various controls by operating switches at any position or positions of steering wheel.
This resulted in the installation of many switches on the steering wheel, causing problems in terms of durability, stability of contacting parts, etc. because of the complicated construction of the coupling parts connecting the steering wheel, which is a movable part, with the fixed part of the car body. In the case of flexible cable connection at the coupling part instead of using a contacting system, many switches installed at the steering wheel result in making the cable lose its flexibility because of a number of cable conductors required. The above not only has a detrimental effect on the operation of the steering wheel, but also causes a danger of accidents resulting from breaking-off of wires. In other words, the use of flexible wire referred to above has the defect of requiring much time and labor for wiring, checking, repairing. Accordingly, whether the coupling parts are of the contacting system type or of the cable system type, it is desirable to reduce the number of coupling parts as much as possible in order to connect the switching part on the steering wheel side with the car body side.
To attain the above purpose, there have conventionally been many proposals, which, however, are not put into practical use because of expensive costs, complicated construction, and a possibility of false function due to delicate construction which may be influenced by noise, temperature and other factors.